It is common practice today to place a beverage container, such as a soft drink or beer can, into a sleeve of foamed polystyrene or the like for the purpose of insulating the beverage container, particularly in warm climates, and also to make the container easier to hold. Additionally, the sleeve can absorb condensation which might form on the can, tending to protect surfaces on which the sleeve containing the beverage container might be placed.
Whether the sleeve is made of a rigid polystyrene foam or a relatively soft, pliable polyurethane foam, the sleeve amounts to little more than a tubular length of thermally insulating material with exposed end edges. Particularly if the sleeve is made of a substantially rigid polystyrene foam, the sleeve is commonly provided with end members to keep the foam intact and to add strength to the overall structure. At the bottom of the sleeve, the end member can constitute a closure for the bottom end of the sleeve to prevent the beverage container from slipping out through the bottom and to also perform a protective function.
However, the bottom closure members which have been provided in the past have numerous disadvantages in that they frequently conduct moisture to the surface on which the sleeve and beverage container is placed and often forms a vacuum within the sleeve so that it is difficult to extract an empty container from the sleeve. Some such closures are slippery and allow the sleeve to slide on a table surface. Additionally, moisture often collects in the bottom of the sleeve. As to assembly, previously used closures have relatively small space for attachment to the tubular portion of the sleeve, and are relatively difficult to assemble because the closure must be positioned and held while being glued together.